Gresini to withdraw MotoGP and Moto2 teams from Valencia finale

Team boss Fausto Gresini also said his organisation would miss the end of season tests which follow as they struggle to come to terms with Simoncelli's death.

The Italian had joined Gresini for his first season of MotoGP in 2010, and after a breakthrough 2011 had agreed to stay with the team for next season despite Honda initially pushing him to move to the works team.

"The only certainty is that my team won't participate in the upcoming Valencia Grand Prix and in the tests programmed after the race," Fausto Gresini is quoted as saying by Corriere dello Sport.

"The day after you suffer even more. Everything happened so fast, I'm lost for words. I know our job is dangerous, that risk is part of the game, but you always hope nothing happens.

"When it does happen and you find yourself in the middle of it everything changes, it's difficult to accept it.

"The crash was caused by a sequence of incredibly negative circumstances, the bike that moved towards the inside of the turn instead of the outside, being run over on the widest track of the season.

"I have many images from these two years spent together resurfacing inside my mind. Marco was spontaneous, he would always do what he thought, with a great heart and always radiant. I can't remember him getting angry even once.

"He was always honest with himself and with the others, a guy who loved challenges, and we, his team, were just an instrument to realise his dreams and to unleash his passion."